Effect of training system on photosynthesis and fruit characteristics of Cabernet Sauvignon

【Objective】To investigate the effect of training system on photosynthesis and fruit quality,andevaluate the performance of‘Modified VSP'(slope trunk with a vertical shoot positioning training system)and F-MT(Fan training system with multiple trunks) in Xinjiang of China.【Methods】the two trainingsystems were taken in‘Cabernet Sauvignon'. The photosynthetic parameters and light response curveswere determined by LI-6400 portable photosynthesis system. The canopy characteristics and grape com-position were measured. The total content of anthocyanins was analyzed by HPLC-MS.【Results】The re-sults from the two-year study confirmed that in‘Cabernet Sauvignon',M-VSP resulted in improvementin photosynthesis of the leaves and grape composition compared with F-MT.The improvement mainly re-sulted from the following significant changes made by M-VSP:(1)bigger total leaf area per vine;(2) im-proved light transmittivity;and(3) increased the PAR level in the fruiting zone. Compared with the leavesin F-MT system,the leaves from vines trained to M-VSP had the most powerful growth potential,thefastest metabolic rate and the excellent ability to utilize weak light. Additionally,M-VSP not only had thesmaller and looser clusters,but it also produced the berry with desired wine-making quality due to the heavier seed and skin,and more seeds per berry. The total soluble solids and anthocyanin content at har-vest were increased as well. However,M-VSP had lower yield than F-MT.【Conclusion】M-VSP showedbetter performance in improving the quality of wine grape than F-MT.